DIY: Build your own positive battery cable 9456836 for the 850

[jreed]

This is a quick write up to show how I built a new positive battery cable for my ‘97 855 GLT (~172k miles). I decided to do this after the original cable failed after about 15 years and then the aftermarket replacement failed after about 2 years.

I had to replace the original battery cable 2 years ago because it developed high resistance between the battery terminal and the wire. I bought an aftermarket cable from IPD, labeled RAMAC (based in Minden NV), which based on the Chinese characters on some of the protective sleeving may have actually been manufactured in China. The RAMAC cable failed in service after 1.5 years in the same area as the original, with high resistance between the battery terminal and the wire. The symptoms were an intermittent no crank, with high (0.7 – 1.1 Volt) voltage drop between starter and positive battery post. Pushing with fingers sideways on the wire leading into the crimp would reduce the voltage drop to the point where the car would start.

I removed the RAMAC cable from the car and sliced it apart… cross-sections of the failed crimp are posted here: https://www.matthewsvolvosite.com/forums ... =1&t=61435

The RAMAC cable had only a small region of the terminal crimped to the wire. The rest of the cavity in the crimp section was open. The heat shrink was not adhesive lined, so the seal was not very good to keep out moisture. As BEJinFbk pointed out, the crimp may have corroded to the point that the resistance increased.

RAMAC cable: Poor crimp + non adhesive-lined heat shrink = eventual failure.

Ramac p03.jpg (157.04 KiB) Viewed 7800 times

As a temporary measure, I installed a “bolt on” battery terminal to keep the car running and get me by while I sourced and built a replacement cable. This worked fine but I wouldn't trust it to last for the long term because the connection is not soldered or crimped and there is no real corrosion protection.

Temporary 'bolt-on' terminal to keep car running.

Ramac p05.jpg (235.63 KiB) Viewed 7800 times

I was inspired by MrPc, who soldered the terminal onto the wire. He wrote up his work here: https://www.matthewsvolvosite.com/forums ... =1&t=60223
I found a great source for battery cable parts and supplies (http://www.genuinedealz.com). They have great prices, good email communications, free quick shipping by priority mail, and have a range of high quality tinned copper wire, adhesive lined shrink, lugs, terminals, solder slugs, sheathing, etc. They're great and I would buy from them again.

The battery terminals on the Volvo have a screw post on the top for additional positive connections. I couldn’t find a source of battery terminals that already have a screw post, so I decided to add an extra 6 AWG wire to the terminal and splice it directly to the positive wires.
I also decided to upgrade the gauge of the main wire between the starter and positive battery terminal from 2AWG to 1AWG. To fit the 1AWG and 6AWG wire, I bought a 0 AWG terminal. The fit was good.

New components for building cable

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The picture above shows the connectors, heat shrink, sheathing and wire: the 1AWG main cable (3 foot length), the 6 AWG second cable (1 foot), the 0AWG battery terminal, the 1AWG lug which fits on the starter solenoid, the expandable sheathing for protecting the wires, and the adhesive lined heat shrink (3/4” diameter). The wires and terminals were all tin plated, which made wetting the solder very easy.

Step-by-step:
To solder the starter solenoid lug to the 1AWG cable, strip off enough insulation so that the exposed wire will just fit inside the lug without leaving a gap of bare wire.

Stripped length of 1AWG wire to fit into lug.

Wire_stripped_ p02.jpg (223.47 KiB) Viewed 7800 times

Heat up the lug using a torch and melt some 60Sn/40Pb or similar solder into the lug. I used rosin core solder, about 0.05” diameter, and I melted in a good 10” length until I could see a puddle of molten solder inside the lug. If you don’t buy good quality lugs, watch out for leaks when you fill the lug with molten solder.

Using torch to heat lug and melt solder

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With the lug still hot, insert the end of the stripped wire. Pre-tinned wire makes it easier for the solder to wet the wires. Apply more heat with the torch while pushing on the wire. Apply more solder to the wire while heating. The solder should melt into the wire. The wire should sink in until it bottoms out inside the lug.

"Heating in" the wire to the solder-filled lug.

Insert_wire_into_connector_ p04.jpg (155.42 KiB) Viewed 7800 times

The insulation may brown, melt and even burn a little at the edge – this seems inevitable and is probably OK. I cleaned off the burned parts afterwards with a wire brush.

Bottoming out

Heat_wire_while_adding_solder_and_pushing_into_connector_ p05.jpg (150.83 KiB) Viewed 7800 times

Next cut a length of adhesive-lined heat shrink and put it over the lug and wire. Apply indirect heat to the heat shrink (I used the torch) until it is evenly tight around the connection and the adhesive lining can be seen to have squeezed out a little bit around all the edges. This insures a good waterproof seal between the lug and the wire insulation to keep the connection from corroding.

Adhesive lined heat shrink

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Apply heat till adhesive squeezes out around all edges

Heat_the_Heat_Shrink_ p07 .jpg (137.69 KiB) Viewed 7800 times

I then applied some expandable sheathing over the wire and affixed it at the lug end with a second piece of heat shrink. This part of the job may be optional. I used the sheathing to protect the wire from abrasion and heat in the engine compartment. It wasn’t expensive ($6/10’). An alternative is plastic split loom, which may be less expensive (Harbor Freight has some for about $3/8’).

Apply protective sheath

Abrasive_wrap_around_Heat_Shrink_ p0701.jpg (163.3 KiB) Viewed 7800 times

The lug bolt hole diameter that I bought was 1/4” which was the smallest size. When I did a test fit, I found that the starter solenoid bolt is too big for 1/4”, so I used a round file to open up the hole just the right amount for the bolt. I measured the diameter of the starter bolt to be 8mm (~0.31”). A lug with an opening of 5/16” should be just about perfect. This size is available at genuinedealz or others.

At the battery terminal end, I stripped and lined up the 1AWG and 6AWG wires. I also put the heat shrink over the wires well back from the end (if you have 3/4" or larger diameter heat shrink you can slip the heat shrink over the lug and wires from the starter end after soldering).

Slip the heat shrink into place before soldering

Battery_Terminal_and_wires_ p08.jpg (183.69 KiB) Viewed 7800 times

Test fitting the wires in the terminal, I decided it was better to bevel off the insulation on the 6AWG a bit so that the two wires would fit straighter into the terminal.

Beveled insulation to allow wires to enter straighter into terminal

Battery_Terminal_and_wires_ p09.jpg (190.98 KiB) Viewed 7800 times

I heated up the terminal and melted about a foot of solder into it. Then I put the two wires in and heated some more, while applying more solder to the wires.

Heat terminal while applying solder

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I applied solder until I saw the terminal was full and brimming over with molten solder.

Terminal filled with solder

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I cleaned up the burned and browned insulation with a brush and a knife.

Then I slid the heat shrink over the end of the terminal and heated it to fit.

Heat shrink on terminal

Battery_Terminal_heat_shrunk_ p12.jpg (200.26 KiB) Viewed 7800 times

Next it was time to connect the 6AWG wire to the original bundle of terminal-top positive battery wire. If you haven't already done so, now is the time to disconnect the battery cables and remove the battery from the car.
The original cables are built up with multiple (6 or 7) smaller wires, crimped into one connector plus another small gauge wire.

Original Volvo wire bundles and crimps

Original_B+_wiring_terminals p13.jpg (309.75 KiB) Viewed 7800 times

I cut the crimp terminals off and stripped back about 2” of insulation from each wire. I cleaned the wire ends with some fine (320 or 400grit) sandpaper to remove oxidation.

Terminals clipped and wires stripped

B+_wiring_stripped_and_ready_for_splice p14.jpg (271.55 KiB) Viewed 7800 times

I applied a little rosin flux to the wires and then wrapped the new 6AWG wire firmly around the original Volvo wires, forming a good clinched mechanical bond. Then I applied heat and solder until the whole joint was wetted and filled with solder.

Wires wrapped around each other and soldered together

Soldered_splice p15.jpg (176.19 KiB) Viewed 7800 times

When the joint cooled, I cleaned up the flux residue with a wire brush and then wrapped the joint with silicone fusion tape. I had applied a piece of 1/2” diameter heatshrink in advance, but the heat from soldering shrank it too much to fit over the joint and I had to cut it off. I would use 3/4” heat shrink next time, and protect the heat shrink during the soldering process.
With all the soldering and heat shrinking done, it's time to put the battery back into the car and attach the cable to the starter solenoid and the battery terminal. So far, it's working well.

Finished installation

Finished installation p16.jpg (204.48 KiB) Viewed 7800 times

Good luck!

[MrPc]

Nice job! The adhesive filled heat shrink and cable sheathing certainly adds a professsional touch.

If you don't mind my asking...what did the total bill come to?

Also, do you notice any difference in cranking speed after switching to the 1AWG cable? If not, would you consider just soldering the new battery terminal and 6AWG wire to the end of the old Ramac cable where you cut the terminal off, if you had to do it again?

[erikv11]

This is fantastic, thanks for documenting and then posting.

[jreed]

Thanks for the feedback guys!
I decided to get rid of the Ramac cable entirely because when I inspected the starter-end of the Ramac cable, I saw that it was poorly crimped, with some wires not enclosed in the primary crimp and cut insulation in the secondary crimp. I figured it was just a matter of time before I'd be back in there again, fixing it. So I decided to go for all new, all high quality.

Poor crimp on the old Ramac cable, at starter solenoid end

Cut_insulation_on_Ramac_crimp p18.jpg (131.49 KiB) Viewed 7792 times

At Genuinedealz, this was my bill of materials:
Heavy Duty Cable Lug Tinned Copper 1 AWG or 2 AWG Gauge Stud Size 1/4 Inch $2.31
1 AWG Gauge Battery Cable Tinned Copper Marine Wire Red by the foot. (3 feet) $11.85
Heat Shrink Tubing Adhesive Lined 3/4 Inch Diameter 1 ft Red $2.43
Braided Expandable Wire Sleeving 1/2" 10 ft Roll Red $5.81
Battery Terminal Straight Copper Tinned - Positive - 1/0 AWG $4.20
6 AWG Gauge Battery Cable Tinned Copper Marine Wire Red by the foot (1 foot) $1.24
Total = $27.84

I already had the tools and supplies (wire stripper, torch, solder).

[cn90]

Wow,

Very professional job. Learned something new today!
I don't need this DIY but when I do, this DIY will be great.
Thanks!

[rspi]

Do you know what kind of charge is reaching your battery now? When my cable was "bad" my normal charge rate was something like 12.4 - 12.8 volts (according to my ScanGauge-live data). I did the repair that you referenced, where I cleaned the connections and soldered the positive battery terminal. Now my charge rate is between 13.7 and 14.1 volts.

[jreed]

Thanks for asking! Now I'm curious to go and measure the voltage at the battery now that there is a bigger and hopefully better cable in place. The last time I measured a few months ago, it was around 12.6V at the battery with the engine running. I'll go out and see what I'm getting now and post it up.

[ThommyKent]

Connector crimper

crimper.jpg (9.35 KiB) Viewed 7726 times

What you did was well done and you`ll probably get away with it. The problem is that those connectors are meant to be crimped and relying on solder to mechanically fasten the wire to the connector is slightly dubious. You really need this tool to do it correctly.

[cn90]

Thanks TommyKent,

Learned something new.
It looks like crimping is the way to go.

A related thread:
http://www.jalopyjournal.com/forum/show ... 236&page=2

PS: I wonder if one can crimp using a bench vise, just make up some metal pieces as wedge and use the vise to crimp it.

[ThommyKent]

You could make some pieces to emulate the crimp pattern and use a vise. That`s a great idea! What ever you do don`t just smash it flat.
Here`s more info

Crimping tool
http://www.delcity.net/store/Heavy-Duty ... er/p_10383